Trouble with Lambs

Tuesday, May 02, 2023

Stock Journal Technical Column January 2023 

Author: Emma Shattock, Elders Livestock Production 

Are you having trouble with your lambs? Are they scouring, losing condition or worse? This has been a common problem and you are not alone. Let’s take a closer look at what might be going on.

The Background

Before we isolate some common causes let’s look at how we got here. For the most part, we can blame a very wet spring. In some areas, this is on the back of large summer rains at the start of 2022 which helped some parasites, including barber’s pole worm, build up numbers. Just like the challenges we have seen in broadacre agriculture, the mild, wet environment has provided ideal conditions for all sorts of parasites flourish.

From an animal perspective, the wet spring was preceded by a dry start in many areas, which already provided challenging conditions for young stock. To cap it off, much of the late spring feed looked better than it actually was, with both intakes and quality often lower than expected.

Dry feed has followed suit and has been lower quality than expected for this time of year. In areas that dried off before the October and November rains, paddocks were left with large quantities of feed that was ‘washed out’ and lower in energy than cereal straw.

All this pressure for a lamb, which already has a more naïve immune system than an adult ewe, made them susceptible to whatever challenges came their way. Add in the stress of weaning or change of feed and these parasites and diseases took over.

The Challenges

The most common problem facing lambs in many areas of the state this year is a much higher than average worm burden. Properties that have previously had a limited need for worm control programs have returned high worm egg counts, often over 1000 eggs per gram. This has been seen across a range of climates and production systems, from pastoral and low rainfall through to high rainfall areas. The late rains and limited access to stubbles before Christmas have also allowed worms to breed quickly and lambs return high egg counts 6 weeks after drenching. Remember that the worm population exists both in the sheep and on the pasture.

Barber’s pole worm has been much more prevalent across the state this year. Unlike the other ‘scour’ worms, barber’s pole sucks the blood of sheep and can quickly become fatal. This worm breeds exceptionally fast, with females laying up to 10,000 eggs per day. Be on the lookout for lethargy, anaemia (pale gums and inside eyelids) and a fluid swelling under the jaw called ‘bottle jaw’.

Other serious conditions have also been encountered, although less common. Several outbreaks of Salmonella and E. coli have caused very watery scours and large losses of stock in a short space of time. Respiratory disease has also been reported. Veterinary advice should be sought for these cases urgently.

Moving forwards

There are several courses of action to get your lambs back on track:

  1. Check for worms. If in doubt, organise a worm egg count to determine the worm burden of your flock. Drench with an effective drench as needed.
  2. Call a vet if you are experiencing quick decline, continual or large losses of stock, very watery scours or anything else that seems unusual.
  3. Give lambs a quality, balanced diet. Get feedstuffs, particularly hay, tested for energy and protein. Lambs need an energy dense, high protein diet for growth, supplemented with balanced minerals and vitamins for growth.
  4. Keep in mind which paddocks you will need for lambing and start taking steps now to reduce the worm burden here.

Get out and have a closer look at your lambs. In some cases, it hasn’t been until mobs were yarded that it became apparent they weren’t gaining weight despite being on a high quality diet. Remember, prevention is better and cure!